1. The Field of the Invention
The present invention is directed generally to methods and apparatus for preventing diseases in poultry. More specifically the present invention is related to methods and apparatus for immunizing poultry against diseases caused by bacteria, viruses, and parasites.
2. The Relevant Technology
Commercial poultry husbandry and breeding practices have resulted in immune system deficiencies in chickens making disease more prevalent and devastating to the birds.
Coccidiosis is a disease which costs the poultry industry hundreds of millions of dollars annually. This disease is primarily caused by parasites from the genus Eimeria. These parasites have short, direct life cycles and high reproductive potentials which intensifies the potential for outbreaks of disease, especially where 15-30,000 chickens are housed in total confinement. McDougald, L. R., Reid, W. M., Coccidiosis, Diseases of Poultry, (B. W. Calnek et al. eds., 1 0th ed. 1997).
Eimeria parasites multiply in the intestinal tract where they cause tissue damage. This further results in the interruption of feeding and digestive processes or nutrient absorption; dehydration; blood loss; and increased susceptibility to other disease agents. Further, immunosuppressive diseases may act in concert with coccidiosis to produce a more severe disease. Id.
Coccidia are almost universally found wherever chickens are raised, and especially in broiler farms where the chickens are kept for only about 6-8 weeks prior to market. The ubiquitous nature of coccidia in poultry precludes the possibility of elimination or prevention of coccidia by quarantine, disinfection, and sanitation. Id.
Coccidial infections depend largely on the number of parasite oocysts ingested and on the immune status of the bird. Characteristics useful in identification of the species of parasite include location of the lesions in the intestine; appearance of the gross lesion; oocyst size, shape and color; location of parasites in tissues; etc. Id.
Prevention of this disease has been attempted by supplying young poultry with continuous medication of anticoccidial drugs. Vaccines against coccidiosis have met with limited success and have been used mostly in breeders and in turkeys. Conventionally, vaccination of broilers was rare due to the risk associated with the birds contracting a light infection from the vaccine, which could affect weight gain, feed conversion, and skin pigmentation. Id.